Five Science Experiments You Can Do at Home

Science is something we can do every day and we don’t need fancy equipment! We can run our own experiments at home, using the same methods as scientists in the lab.

All scientists, whether they are in Europe or Auckland, or on the International Space Station, start with a load of questions.

Once we have a really good question, we can start to guess what we think the answer is. This is called making a hypothesis. The next thing we do is run an experiment. During our experiment, we make lots of observations and take notes about what we see. Was our hypothesis correct, or did our experiment surprise us? Do we have more questions to test now?

This is called the scientific method, or tikanga pūtaiao.

1. Use a wire coat hanger to learn about sound

What you need

• Wire coat hanger
• String
• Scissors
• Metal spoon
• Other kitchen utensils

How to make it

• Cut two pieces of string about 30cm long.
• Tie each of the pieces of string onto the bottom of the coat hanger.
• Tie the other end of the string into a loop that is big enough for your finger to slide through.

Experiment

• Put your two index fingers in the loops and suspend the coat hanger from your fingers.
• Have someone gently tap the coat hanger with the metal spoon. What do you hear?
• Now with the string loop still on your fingers, put your fingers in your ears and lean forwards until the coat hanger is not touching your body.
• Have someone gently tap the coat hanger with the spoon again. What do you hear? Is there a difference?
• What is vibrating and causing a sound to be heard?
• Where does the vibration travel?
• How can you stop the vibration?
• Can you make another instrument out of a plastic or wooden coat hanger? How does the sound compare? What if you use a different kitchen utensil to tap the coat hanger? How does that change the sound?

What’s going on?

When the coat hanger is tapped, it starts vibrating. When vibrations travel through air, the energy spreads out, so the sound reaching our ears is quieter. When we put our fingers into the loops and into our ears, we allow the sound to travel through a solid (the string and our fingers). When vibrations travel through a solid, they don’t spread out as much, and so the sounds are louder.

2. Make your own compass to learn about magnetism

What you need

• Fridge magnet
• Sewing needle
• Bowl of water
• Piece of foam or a leaf

How to make it

• Take the sewing needle and stroke it with the magnet from top to bottom. Repeat this action about 25 times. Make sure you are only stroking the needle in one direction. Its safest to do this part with the needle laying on a table.
• This stroking action magnetises the needle. You can check that it is magnetised by using it to attract and pick up another needle.
• Fill a bowl with water and float the foam or leaf in the water with the needle laying on top.
• The needle will slowly rotate until it is pointing North.

Experiment

• Repeat the experiment with another needle, does it point the same way?
• Can you check that the compass is correct? (Maybe download a compass app, or use landmarks around your house to find true North)
• What happens if you hold a magnet close to the compass?

What’s going on?

The Earth’s core is made up of liquid iron and nickel. This amount of metal creates an enormous magnetic field around the entire earth! Once magnetised, the metal needle of a compass aligns with the Earth’s magnetic field to show the direction of magnetic North.

Needles contain iron which is attracted to magnets. In a regular needle, the magnetic parts of the iron are all pointing in different directions. When you magnetise the needle, you cause all the magnetic parts to point in the same direction. This causes the needle to become a temporary magnet. This magnetism will disappear over time as the magnetic parts rotate back to their random orientations.

The earth acts as a giant magnet with two poles that attract the needle of a compass. Although large, the magnetic field of the Earth is relatively weak. Most magnets have a stronger magnetic field than the earth. Holding a magnet close to a compass will cause the needle to change its direction.

3. Make a rain gauge and learn about your local weather

A rain gauge is simply any container that measures how much rain has fallen. Making your own rain gauge, and checking it regularly, will tell you exactly how much rain is falling at your home.

What you need

• Large plastic bottle
• Scissors
• Ruler
• Permanent marker
• Measuring jug or measuring cups
• Handful of rocks
• Notebook or spreadsheet

How to make it

• Cut the top off the bottle, this will become the funnel for the rain gauge.
• Create a zero line around the bottom of the bottle.
• Use the ruler and marker and measure out 10mm increments from the zero-line going upwards. Alternatively, you can attach the ruler straight onto the bottle, placing the zero onto the zero line.

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• Put some heavy rocks in the bottom of the bottle and pour in water until it reaches the zero line.
• Leave the bottle outside, somewhere where it can fill up with rain.

• Measure the amount of water sitting above the zero line. Take your measurements in millimeters, using a ruler to get a more accurate measurement.
• Write down your measurements along with the date and time.
• Empty the rain gauge and re-fill it with water up to the zero line.

Experiment

• Record how much rain has fallen in a set amount of time. You might choose to check and record your gauge every day (24 hours), or every other day (48 hours), or just once a week (168 hours). Always try to check the rain gauge at the same time of day, so make sure you pick a time that will work!
• Record your measurements in a notebook or spreadsheet. Record the date, the amount of rain, and any other information you like. This is called your data.
• Create multiple rain gauges for your family and friends and record how much rain falls at their homes too. How are their measurements different from your data?
• If you use a bottle of a different size, do you get a different reading? Make two rain gauges with different bottles to test your prediction.
• Compare your data to other data sets. How does your rainfall data compare to the predicted rainfall from the Met Service Rain Radar? How does your rainfall data compare to the average rainfall in Auckland each month?
• Compare your rainfall data to the changes in Auckland’s dam levels. Does the dam level go up when you record a lot of rain?

4. Make a wacky wobbler toy and learn about balance

What you need

• Cork (ask your parents)
• Toothpick
• Skewers
• Blue-tack or modelling clay

How to make it

• Push the toothpick into the bottom of the cork
• Push the two skewers into the sides of the cork, about 1/3 of the way down.
• Create 2 blobs of blue-tack and attach them to the end of the skewer arms.
• You might need to change the angle of the arms or add more blue-tack to get your wacky wobbler to stand up. Just keep tinkering until you get it right!

Experiment

• Try adding more arms to the wobbler, what happens?
• Try adding more weight to the wobbler, what happens?
• When you change the angle of the arms, how does it affect the wobbling?
• What is the smallest surface you can balance the wobbler on?
• Can you balance the wobbler on your head, finger, toe or nose?
• Can you redesign the wobbler or make another kind of balancing toy?

What’s going on?

The heavy blue-tack lowers the centre of gravity of the wobbler. Most of the weight is now below the toothpick, which acts as the pivot point. The stops the wobbler from falling off things.

The long arms act to stabilise and slow down the wobbling. It’s similar to how gymnasts put their arms out wide on the beam, or tight-rope walkers sometimes use a long pole to balance. We can improve our own balance this way too. If you stand on one leg, it will be much easier with your arms thrown wide, than with them pinned to your sides, or held above your head.

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5. Make a cartesian diver and learn about pressure

What you need

• Large plastic bottle
• Water
• Soy-sauce fish (or use a tiny sauce packet, pen cap, plastic straw)
• Blue-tack or paperclip

How to make it

First, find your diver. I like to use soy sauce fish, but you can make this with any small item that can fit through the top of your bottle, and that can hold a bubble of air.

• Pop your diver into a cup of water, notice where it floats in the cup. You want it to float right in the middle of the cup.
• If the diver is floating at the top, you need to add some weight to it using the blue-tack or paper clips.
• If the diver floats at the bottom, it is too heavy, and you need to remove some weight. For the soy sauce fish you might need to remove some of the soy sauce.
• Once you have the diver floating perfectly, you can add it to the plastic bottle.

• Fill the bottle to the brim with water, you can’t leave any other air in the bottle.
• Put the lid on tightly.
• Squeeze the bottle as hard as you can, what happens to the diver?

Experiment

• Try making the different types of diver.
• Try adding and removing weight from your diver, does this affect how hard you have to squeeze?
• Can you have multiple divers in the bottle at once?
• Decorate you diver to look like a fish or jelly.

What’s going on?

It’s very difficult to squeeze water, but quite easy to squeeze air. Imagine the difference between squeezing a regular balloon and a water balloon. The diver we made contains a small air bubble. When we squeeze the bottle, we change the pressure inside. The water stays the same, we are not strong enough to squeeze it, but this little bubble is squeezed and shrinks. The squeezed and shrunken bubble is now heavier. This change in bubble pressure causes the diver to sink.

Remember: have fun, be safe, clean up afterwards…and don’t let your dog into the lab! (Unless he IS a Lab!)