The harder the material, the better the sound travels through is.

When you hear your brother singing in the bathroom, it shows that sound travels through liquids.

Sound can't travel through vacuum.

We can hear the loudest sound if it travels through the air.

Sound travels best through solids.

A vibration is a very quick movement back and forth.

Sound travels because vibrations travel.

Trapping the sound vibrations makes the sound quieter.

The unit we use to measure the volume of sound is newton.

The volume of a sound is how high or low the sound is.

Very loud sounds can damage our ears.

We can use sound level meter to measure the volume of sound.

If there has small vibrations, we can hear soft sounds.

We fit silencers to cars to muffle the sounds.

In the air, we cannot hear the sound properly than it is passing through the solid materials.

Bongos is a percussion instrument.

Bats make low-pitched sounds that we cannot hear.

Pitch is the same as volume of sound.

The pitch of a sound means how high or low the sound is.

The longer the column of air is, the lower the pitch of the sound.

The electric current flows from the negative terminal to the positive terminal of the cell.

Opening the switch means breaking the circuit.

If you have too many cells in a circuit, the bulbs burn out.

Electricity is the flow of uncharged particles.

A cell has a positive terminal and a negative terminal.

Electric current does not need a continuous path.

Electricity can flow many directions in a circuit.

When you make a complete circuit with two cells, you must always put the (+)terminal of the cell to the (+) terminal of the other cell.

Drawing pins are electrical components.

Plastic coating around the metal wires prevents from being electro-cut.

Electricity can't jump from one component to others in a circuit.

If the electricity doesn't have a path to travel on, it stops.

Flat cell means a cell has used up all the chemicals.

When we open the switch, the light will shine.

We need to strip the plastic off the ends of the wires to flow electricity in a complete circuit.

If your circuit has a gap, the electricity can jump over it and can flow through all the components properly.

You can make a stronger cell by joining two cells together.

When we remove one bulb from a circuit, the other bulbs can shine more brightly.

The switch turns the electricity on and off.

When we turn off the light, the circuit break.

Magnets can attract wood and glass.

Magnets can attract or repel magnetic materials.

Metals such as iron, nickel, cobalt are attracted to magnets.

A compass uses a small magnet to point south.

Planet Earth has its own magnetic field.

Magnets can be made in almost any shape or size.

Magnetic fields cannot work through other materials, such as paper.

Magnets can be found in many household items such as fridges and electric toothbrushes.

Opposite poles of magnets will always attract each other.