Floating Egg Experiment
We’re back with another summer camp science session today. If you missed the introduction I recommend you go back and read it as it includes some general tips for all our science sessions.
This week we have another experiment that’s really easy to do and only requires a few simple items from around your kitchen. Here’s what you will need:
- an egg
- a large glass or jar
- some tap water
- food colouring (optional)
If you want to record your experiment – including your predictions, observations and findings – you can also download a copy of my free ‘Science Experiment Report’ sheet and either print it off or, if you don’t have a printer, use it as a template to create your own. Depending on age, kids can either write and/ or draw their observations.
I’ve recorded a video of the experiment, which you will find further down the page. However, I recommend you try the experiment out yourselves first before watching the video, and then you can compare your results with ours.
Safety Tip: Careful when handling food colouring so that you don’t stain clothes or surfaces.
Floating Egg Experiment
Step 1: Fill your glass or jar about half full with tap water.
QUESTION: What do you think will happen if you lower an egg in to the water? Record your predictions.
Step 2: Carefully lower an egg in to the water. What happens? Record your observations.
Step 3: Carefully remove the egg again and add a generous amount of salt in to the water. If you think you’ve added enough, add some more.
QUESTION: What do you think will happen now if you lower the egg in to the water again? Record your predictions.
Step 4: After you’ve let the salt settle (otherwise you won’t be able to see properly) carefully lower the egg in to the water again. What happens this time? Record your observations.
If you have some food colouring, you can do an additional part to this experiment (really it’s two experiments in one) – just carry on with Step 5.
Step 5: In a separate glass or jug, mix some more tap water with some food colouring.
QUESTION: What do you think will happen if you pour the tap water in to the glass with the salt water and the egg?
Step 6: Slowly and gently pour some of the coloured tap water in the the glass with the egg. You want to mix in as little as possible. The best way to this is to slowly pour the coloured water on to the egg, so that it runs off the side of it.
Here’s a short video from when we did this experiment at home:
The answer to this experiment lies in the density of the water. The egg initially sinks in the fresh tap water, because the density of the egg is greater than the density of the water. By adding salt to the tap water, you increase the density of the water. If you add enough salt the density of the water will eventually become higher than the density of the egg, and the egg will float (so if the experiment doesn’t work at first, try adding more salt). For part two of the experiment, the coloured fresh tap water is less dense than the salt water so if you are careful not to pour it in too vigorously and not to let the waters mix, then the coloured fresh water will sit on top of the salt water. The food colouring is just there to let you see the two different types of water better.
All Summer Camp activities are free to make them accessible to as many people as possible. However, if you enjoy the activities and are able to, you can support me with a donation on Ko-fi. Just hit the button below. Every little helps and is much appreciated. Thank you.